Explicație pas cu pas:
a) a+b=43
a,b consecutive
b=a+1
a+a+1=43
2a+1=43
2a=43-1
2a=42
a=42:2
a=21
b=a+1
b=21+1
b=22
verificare: 21+22=43
b)a+b+c=48
a,b,c consecutive
b=a+1
c=a+2
a+a+1+a+2=48
3a+3=48
3a=48-3
3a=45
a=45:3
a=15
b=a+1
b=15+1
b=16
c=a+2
c=15+2
c=17
verificare:15+16+17=48
c)a+b=26
a,b pare consecutive
b=a+2
a+a+2=26
2a+2=26
2a=26-2
2a=24
a=24:2
a=12
b=a+2
b=12+2
b=14
verificare: 12+14=26